The present invention relates to blocks useful for structural purposes, such as walls, and more particularly to such blocks which are made of poured concrete and configured so as to interlock to form a sturdy wall construction.
There are many situations in which it is desirable to construct walls by simply stacking wall blocks in courses upon one another, and yet have these walls be sturdy and resistant even to strong sideways forces which may tend to act upon them.
For example, it is desirable that retaining walls for earth embankments, or for the storage of sand, gravel, or the like, be capable of being made from a single row of stacked blocks, while being highly resistant to the forces which the material being retained exerts upon the wall.
If such blocks are flat-faced, then the only factor which contributes to such resistance is the friction between adjoining blocks, which is a function of their weight and surface roughness.
Weight can obviously not be increased indefinitely. Surface roughness is also not unlimited because, if excessive, it permits the escape, between adjoining blocks, of the material to be retained and it can even be the cause of reduced friction.
The prior art has therefore proposed the use of blocks which are not flat-faced, but which exhibit various configurations of "ins and outs" so that, when the blocks are stacked to form a wall, these ins and outs will interlock and thereby provide the desired structural sturdiness. However, these block configurations have left something to be desired. In some cases the specific configurations were quite complicated and therefore difficult and expensive to manufacture. In other cases, several different configurations had to be provided to form corners in the walls to be erected from these blocks. In still other cases, the configurations of ins and outs were simply inadequate for the task and had to be supplemented by separate reinforcing means.